Abstract

Thin-film solar cells have been fabricated from Cu(InGa)Se2 films which were deposited by four-source elemental evaporation with [Ga]/([In]+[Ga]) from 0.27 to 0.69 corresponding to a band gap from 1.16 to 1.45 eV. The films were intentionally deposited with no grading of the Ga and In to avoid gradients in their electrical and optical properties. X-ray diffraction, energy-dispersive x-ray spectroscopy, and Auger electron spectroscopy show that the films have uniform composition with no change in structure and morphology. Glass/Mo/Cu(InGa)Se2/CdS/ZnO devices have open-circuit voltage increasing over the entire band gap range to 788 mV and 15% total area efficiency for band gap less than 1.3 eV, or [Ga]/([In]+[Ga]) less than 0.5. A decrease in device efficiency with higher Ga content is caused primarily by a lower fill factor. Analysis of current–voltage and quantum efficiency measurements show that this results from a voltage-dependent current collection.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call